In recent years, compactness, high output, and high quality have been required in rotary electric machines such as electric motors or generators. With regard to downsizing rotary electric machines of this kind, armature windings that have concentrated windings in which conductor wires are wound onto individual armature core teeth have been used with a view to downsizing coil ends, which do not generate effective magnetic flux. However, armatures that use armature windings of distributed winding construction that can suppress torque pulsation and increase output are in demand. In addition, rectangular conductor wire, unlike thin circular wire, enables reductions in winding resistance and increases in space factor, but because it has great rigidity and is difficult to deform, production of armature windings has been difficult.
Now, in contrast to concentrated windings, which are configured by winding conductor wires onto individual teeth, windings that are configured by winding conductor wires into slots that are separated by greater than or equal to two slots are designated “distributed windings”. In other words, distributed windings are wound such that a conductor wire that extends outward from one slot spans two or more consecutive teeth and enters another slot.
In conventional rotary electric machines such as that described in Patent Literature 1, a reference unit of an armature winding has been produced by producing a helical first intermediate coil by winding a rectangular conductor wire a plurality of times into an edgewise winding (a coiling step), producing a second intermediate coil that has a set outer circumferential shape by bending and shaping the first intermediate coil using a pressing die (an outer circumference forming step), producing a third intermediate coil that has a circular arc-shaped semicircular portion by bending and shaping a first coil end of the second intermediate coil using a pressing die (a circular arc forming step), forming a lane changing portion by bending and shaping the first coil end of the third intermediate coil using a pressing die (a lane changing portion forming step), and bending a second coil end of the third intermediate coil radially inward using a pressing die (a bending step).